1. Field of the Invention
The present invention relates to a mobile communications system such as a cellular telephone system.
2. Description of the Related Art
In a conventional mobile communications system, a number of base stations are provided, and a mobile station executes handover between the base stations in accordance with movement to continue communications. Recently, development of a mobile communications system employing OFDM (Orthogonal Frequency Division Multiplexing) system has proceeded (cf., for example, 3GPP, TR25.814 (V7.1.0), “Physical Layer Aspects for Evolved UTRA”).
As restriction of time synchronization is smaller as compared with the CDMA (Code Division Multiple Access) system, in the mobile communications system employing OFDM (Orthogonal Frequency Division Multiplexing) system, searching the base station without using a neighbor base station list which has been transmitted from the base stations to the mobile station, by the mobile station, has been reviewed. This aims to reduce overhead of an informative channel over which neighbor base station information is transmitted.
Even in the mobile communications system employing OFDM, however, reduction of the processing load on searching the base stations and enhancement of the searching efficiency have been highly requested due to limitation of the power consumption.
The development of the mobile communications system employing OFDM has proceeded, but reduction of the processing load on searching the base stations and enhancement of the searching efficiency have been highly requested due to limitation of the power consumption.